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Coracohumeral ligament

The coracohumeral ligament (CHL) is a strong, broad fibrous band that extends from the base of the coracoid process of the scapula to the greater and lesser tubercles of the humerus. It reinforces the superior aspect of the glenohumeral joint capsule and plays a key role in stabilizing the shoulder, particularly in preventing inferior and posterior translation of the humeral head.

The CHL blends closely with the rotator cuff tendons, especially the supraspinatus and subscapularis, and forms part of the rotator interval capsule, which is critical for maintaining joint stability during arm rotation.

Synonyms

  • Superior glenohumeral ligament (partial overlap, though distinct)

  • Coracocapsular ligament

  • Coracohumeral band

Location and Structure

  • Origin: Lateral border and base of the coracoid process of the scapula.

  • Course: Extends laterally and inferiorly across the superior aspect of the glenohumeral joint, reinforcing the capsule.

  • Insertion:

    • Medial fibers: Blend with the lesser tubercle and the subscapularis tendon.

    • Lateral fibers: Merge with the greater tubercle and the supraspinatus tendon.

  • The CHL also merges with the superior glenohumeral ligament and capsular fibers within the rotator interval.

Relations

  • Superiorly: Subacromial bursa and coracoacromial ligament

  • Inferiorly: Glenohumeral joint capsule and humeral head

  • Medially: Coracoid process and base of the coracoacromial arch

  • Laterally: Greater and lesser tubercles of the humerus

  • Anteriorly: Tendon of the subscapularis

  • Posteriorly: Tendon of the supraspinatus

Nerve Supply

  • Suprascapular nerve and axillary nerve branches provide sensory fibers to the capsular region and surrounding structures.

Function

  • Joint stability: Reinforces superior capsule and limits inferior displacement of humeral head.

  • Rotator interval tension: Maintains structural integrity between supraspinatus and subscapularis tendons.

  • Limits external rotation: Especially in adduction, preventing excessive joint laxity.

  • Supports suspension: Helps suspend the humeral head against gravity when the arm is dependent.

  • Dynamic role: Works with superior glenohumeral ligament and rotator cuff tendons during abduction and rotation.

Clinical Significance

  • Adhesive capsulitis (frozen shoulder): Thickening and contracture of the CHL are hallmark MRI findings; limits external rotation.

  • Rotator interval pathology: CHL degeneration or fibrosis contributes to stiffness and reduced range of motion.

  • Tears or laxity: May occur with shoulder dislocation or trauma, contributing to instability.

  • Post-surgical importance: Over-tightening during capsular plication can restrict motion.

  • Imaging relevance: MRI essential for assessing CHL thickening, tears, or rotator interval adhesions.

MRI Appearance

  • T1-weighted images:

    • Ligament: Low signal intensity (dark), forming a thin, linear band extending from coracoid to humerus.

    • Adjacent fat planes: Bright, outlining the ligament’s course.

    • Thickened ligament in adhesive capsulitis appears as broad low-signal band crossing the rotator interval.

    • Surrounding muscles (subscapularis, supraspinatus): intermediate signal.

  • T2-weighted images:

    • Normal ligament: Low signal (dark).

    • Adjacent joint fluid or edema: Bright hyperintense, providing contrast.

    • Pathology: Thickened or irregular CHL with surrounding bright edema in adhesive capsulitis.

    • Partial tear or strain: focal increased signal within or around the ligament.

  • STIR:

    • Normal ligament: Low signal, distinct against intermediate muscle and bright fat.

    • Abnormal: Hyperintense signal in periligamentous tissue or capsular thickening (edema, fibrosis, inflammation).

    • Excellent for identifying early adhesive capsulitis and rotator interval inflammation.

  • Proton Density Fat-Saturated (PD FS):

    • Normal ligament: Dark, sharply defined linear structure.

    • Abnormal: Bright signal indicating edema or scarring.

    • Best sequence for depicting subtle thickening or loss of fat plane between CHL and subscapularis/supraspinatus tendons.

  • T1 Fat-Sat Post-Contrast:

    • Normal: Minimal enhancement.

    • Pathology: Diffuse or nodular enhancement in thickened ligament and surrounding capsule in adhesive capsulitis.

    • Distinguishes fibrosis (mild enhancement) from active inflammation (intense enhancement).

CT Appearance

Non-Contrast CT:

  • Ligament not easily distinguished; appears as thin soft-tissue band from coracoid to humerus.

  • Indirect signs: Fat plane obliteration or adjacent soft-tissue density in chronic inflammation or fibrosis.

  • Useful for detecting calcifications or ossification within the coracohumeral ligament (rare).

Post-Contrast CT (standard):

  • Enhances surrounding soft-tissue and capsule in inflammation or adhesive capsulitis.

  • May delineate periarticular fibrosis, joint effusion, or capsular adhesions.

  • Helps exclude other causes of shoulder stiffness such as mass or infection.

MRI images

Coracohumeral ligament axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI images

Coracohumeral ligament axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00001

MRI images

Coracohumeral ligament coronal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI images

Coracohumeral ligament sag cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

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coracohumeral ligament 3D MRI AXIAL IMAGE 2

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coracohumeral ligament 3D MRI AXIAL IMAGE